A fiber array spectral translator (“FAST”) system when used in conjunction with a photon detector allows massively parallel acquisition of full-spectral images. A FAST system can provide rapid real-time analysis for quick detection, classification, identification, and visualization of the sample. The FAST technology can acquire a few to thousands of full spectral range, spatially resolved spectra simultaneously. A typical FAST array contains multiple optical fibers that may be arranged in a two-dimensional array on one end and a one dimensional (i.e., linear) array on the other end. The linear array is useful for interfacing with a photon detector, such as a charge-coupled device (“CCD”). The two-dimensional array end of the FAST is typically positioned to receive photons from a sample. The photons from the sample may be, for example, emitted by the sample, reflected off of the sample, refracted by the sample, fluoresce from the sample, or scattered by the sample. The scattered photons may be Raman photons.
In a FAST spectrographic system, photons incident to the two-dimensional end of the FAST may be focused so that a spectroscopic image of the sample is conveyed onto the two-dimensional array of optical fibers. The two-dimensional array of optical fibers may be drawn into a one-dimensional distal array with, for example, serpentine ordering. The one-dimensional fiber stack may be operatively coupled to an imaging spectrograph of a photon detector, such as a charge-coupled device so as to apply the photons received at the two-dimensional end of the FAST to the detector rows of the photon detector.
One advantage of this type of apparatus over other spectroscopic apparatus is speed of analysis. A complete spectroscopic imaging data set can be acquired in the amount of time it takes to generate a single spectrum from a given material. Additionally, the FAST can be implemented with multiple detectors. The FAST system allows for massively parallel acquisition of full-spectral images. A FAST fiber bundle may feed optical information from its two-dimensional non-linear imaging end (which can be in any non-linear configuration, e.g., circular, square, rectangular, etc.) to its one-dimensional linear distal end input into the photon detector.
A problem exists with the prior art's use of a FAST system. The linear array end of the FAST, when input into a photon detector, may become slightly misaligned so that an image produced may be shifted due to the misalignment. Furthermore, the peaks in a spectrum of the sample may not be aligned with the peaks of a known calibrated sample of the same substance and therefore the received peaks may not be calibrated. Additionally, the fibers in the FAST may not allow for a resolution of the resulting image to a degree necessary. The present disclosure, as described herein below, presents methods and systems for overcoming these deficiencies in the prior art.
The combination of calibration and reconstruction methods according to one embodiment of the present disclosure may be useful among fiber optics imaging manufacturers. The calibration and image reconstruction approaches discussed herein are independent of any specific FAST-based imaging applications. Accordingly, it is an object of the present disclosure to provide a method for spectral calibration, comprising obtaining a first image of a known substance using a photon detector and a fiber array spectral translator having plural fibers, wherein said first image comprises at least one pixel; providing a second image of said substance wherein said second image comprises at least one pixel; comparing said first image with said second image; and adjusting at least one pixel of said first image based on said comparison of images to thereby obtain an adjusted image. It is another object of the present disclosure to additionally obtain a first spectrum of said substance from one of said plural fibers wherein said first spectrum comprises at least one peak; provide a second spectrum of said substance wherein said second spectrum comprises at least one peak; compare at least one peak of said first spectrum to at least one peak of said second spectrum; and adjust said first spectrum based on said comparison of peaks.
It is yet another object of the present disclosure to provide a method for spectral calibration, comprising: obtaining a first data set representative of a first image of a known substance, wherein said first data set is obtained using a photon detector and a fiber array spectral translator having plural fibers; providing a second data set representative of a second image of said substance; comparing said first data set with said second data set; and adjusting said first data set based on said comparison of said first and second data sets. It is still another object of the present disclosure to additionally obtain a third data set representative of a first spectrum of said substance from one of said plural fibers wherein said first spectrum comprises at least one peak; provide a fourth data set representative of a second spectrum of said substance wherein said second spectrum comprises at least one peak; compare a part of said third data set representative of at least one peak of said first spectrum to a part of said fourth data set representative of at least one peak of said second spectrum; and adjust said first data set based on said comparison of said third and fourth data sets.
It is a further object of the present disclosure to provide a method for spectral calibration comprising: obtaining a first image of a known substance using a photon detector and a fiber array spectral translator having plural fibers, wherein said first image comprises at least one pixel; providing a second image of said substance wherein said second image comprises at least one pixel; obtaining a first spectrum of said substance from one of said plural fibers wherein said first spectrum comprises at least one peak; providing a second spectrum of said substance wherein said second spectrum comprises at least one peak; comparing said first image with said second image to thereby obtain a bulk shift adjustment; and comparing at least one peak of said first spectrum to at least one peak of said second spectrum to thereby obtain a subpixel adjustment.
It is yet a further object of the present disclosure to provide a method for spectral calibration, comprising: obtaining a first data set representative of a first image of a known substance using a photon detector and a fiber array spectral translator having plural fibers, wherein said first image comprises at least one pixel; providing a second data set representative of a second image of said substance, wherein said second image comprises at least one pixel; obtaining a third data set representative of a first spectrum of said substance from one of said plural fibers wherein said first spectrum comprises at least one peak; providing a fourth data set representative of a second spectrum of said substance wherein said second spectrum comprises at least one peak; comparing said first data set with said second data set to thereby obtain a bulk shift adjustment; and comparing said third data set with said fourth data set to thereby obtain a subpixel adjustment.
It is still a further object of the present disclosure to provide a system for spectral calibration of a known substance, comprising: a photon source for illuminating said substance with first photons to thereby produce second photons; a fiber array spectral translator having plural fibers, wherein said fiber array spectral translator receives said second photons; a photon detector operatively connected to said fiber array spectral translator, wherein said photon detector detects said second photons; a memory unit comprising a first data set representative of a first image of said substance; and a microprocessor unit operatively connected to said photon detector and said memory unit, wherein said microprocessor obtains a second data set from said second photons, compares said first and second data sets, and adjusts said first data set based on said comparison. It is yet still a further object of the present disclosure to further provide a display device operatively connected to said microprocessor unit so as to display an image selected from the group consisting of: said first image, a second image representative of said second data set, an adjusted image representative of said adjusted first data set, and combinations thereof.